Hi aspirant,

Yes you are eligible for airforce after completing inter from open school (NIOS).It is a recognised board all over India.But to join airforce after 12 you need to be a science student and you will have to give the nda exam.If you are able to clear that then ssb procedure will take place which include interview.Also you will have to clear medical test  following which you will be admitted to National defence academy.

Good luck